Conventionally, cooling agents giving refreshing feeling (cool and refreshing feeling) and cool feeling (chilly and refreshing feeling), that is cooling effect, to the skin, the mouth, the nose, and the throat of a human being have been used for tooth pastes, confections (e.g. chewing gum, candy and the like), tobacco, poultices, and cosmetics. As a flavor substance giving such cool and refreshing feeling or chilly and refreshing feeling, l-menthol (L-menthol) has been used widely. However l-menthol has such faults that the cooling effect is insufficient in retainability and when the use amount thereof is increased, the cooling effect is strengthened but it is accompanied with adverse bitter taste.
As the compounds having a cooling effect there have been proposed and practically used a large number of compounds other than l-menthol. Examples of the conventionally proposed compounds having the cooling effect other than l-menthol include 3-substituted-p-menthane (e.g. reference to Japanese Patent Application Laid-Open No. 47-16647), N-substituted-p-menthane-3-carboxamide (e.g. reference to Japanese Patent Application Laid-Open No. 47-16648), 1-menthylglucoside (e.g. reference to Japanese Patent Application Laid-Open No. 48-33069), 3-(l-menthoxy)propane-1,2-diol (e.g. reference to Japanese Patent Application Laid-Open No. 58-88334), l-menthyl-3-hydroxybutylate (e.g. reference to Japanese Patent Application Laid-Open No. 61-194049), 1-alkoxy-3-(l-menthoxy)propane-2-ol (e.g. reference to Japanese Patent Application Laid-Open No. 2-290827), esters of 3-hydroxymethyl-p-menthane (e.g. reference to Japanese Patent Application Laid-Open No. 5-255186), N-acetylglycinementhane methyl ester (e.g. reference to Japanese Patent Application Laid-Open No. 5-255217), (−)-isopulegol (e.g. reference to Japanese Patent Application Laid-Open No. 6-65023), (2S)-3-{(1R,2S,5R)-[5-methyl-2-(1-methylethyl)cyclohexyl]-oxy}-1,2-propanediol (e.g. reference to Japanese Patent Application Laid-Open No. 7-82200), and 2-hydroxymenthylmenthol (e.g. reference to Japanese Patent Application Laid-Open No. 7-118119).
The above-mentioned conventionally proposed cooling agents have cooling effect to some extents, but they are insufficient and unsatisfactory in the retainability of the cooling effect. Also, it is required to improve the sensory stimulating effect.
Accordingly, the object of the invention is to provide innovative menthol derivatives excellent in retainability of cool and refreshing feeling or chilly and refreshing feeling without giving undesirable stimulation, peculiar odor, and bitter taste and usable for cooling agents and sensory stimulation agents.
Also, the object of the invention is to provide cooling agent compositions comprising the innovative menthol derivatives and sensory stimulation agent compositions containing the cooling agent compositions.
Further, the object of the invention is to provide fragrance compositions, beverage or food products, cosmetic products, toiletry products, bathing agents, orpharmaceutical products containing the cooling agent composition or sensory stimulation agent.
Inventors of the invention have made various investigations concerning the cooling effect of various kinds of compounds derived from l-menthol to solve the above-mentioned problems, and have found that the menthol derivatives represented by the following general formula (I) have strong cooling effect and are excellent in retainability of the effects and thus useful for cooling substances and sensory stimulation substances as well. Additionally, inventors have also found that in the case l-menthol is used as a cooling agent, the stimulating odor of l-menthol can be moderated by the menthol derivatives, and with respect to fragrance compositions containing the cooling agent compositions comprising the menthol derivatives represented by the following general formula (I), the fragrance note and remnant fragrance of the fragrance compositions is heightened and the fragrance compositions give high fragrance-improving effects to products mixed with the fragrance compositions. The invention was accomplished based on these findings.